Automated microneutralization: method and comparison with western blot for type-specific detection of herpes simplex...

A novel method for the detection of microneutralization was compared to Western blot for detection of type-specific antibodies to herpes simplex virus in two pregnant patient populations in Vancouver. From an unselected group of women in labor in a tertiary care obstetric hospital (426) and another group of women specially referred for assessment of genital herpes in pregnancy (195) 20 and 88%, respectively, were seropositive for herpes simplex virus type 2 antibodies by Western blot. During the study period, 93 (48%) of the high-risk group were culture positive for HSV-2 and all but one case was verified serologically by Western blot. Therefore, the sensitivity for Western blot in this high seroprevalence group was 99%. The false-negative case had longstanding recurrent infection and on retest was found to be a laboratory error. For microneutralization, type-specificity was especially difficult to distinguish among patients with mixed viral type patterns. Comparing microneutralization to Western blot as the gold standard, sensitivity, specificity, positive and negative predictive values were 84, 78, 97 and 40% respectively, for the referred group and 73, 82, 51 and 92%, respectively, for the unselected group. Poor negative and positive predictive values for the referred group and unselected populations, respectively, demonstrate that microneutralizations are not clinically acceptable for type-specific antibody detection. By contrast, serology by Western blot is very sensitive and apparently highly specific.